GNU/Linux Rapid Embedded Programming

GPIOs in Linux

In a Linux system, GPIO lines can be managed through the sysfs using simple Bash commands; this is the easiest technique we can use to get access to these peripherals. In the following examples, we are going to use the Wandboard but we can redo them on the other systems too but using different GPIO lines, of course.

The sysfs interface to manage the GPIOs are under the /sys/class/gpio/ directory, and if we take a look at its content, we can see the following files:

root@wb:~# ls /sys/class/gpio/
export     gpiochip128  gpiochip192  gpiochip64  unexport
gpiochip0  gpiochip160  gpiochip32   gpiochip96

Files named gpiochip0, gpiochip32, and so on are related to the GPIO controller chips that are the entities that actually manage a GPIOs group. ...